The field of art to which this invention pertains is air-drying unsaturated fatty acid resins, particularly alkyd resins and epoxy esters.
The use of alkyd resins and epoxy esters in air-drying coating applications has been known for many years. One of the problems with the use of these materials, however, has been the time required to effect complete drying of coatings made from such materials. In many applications of some alkyd resins and epoxy esters, it is very desirable to speed up the through-dry of the coatings and to obtain harder films after overnight dry. Many systems, particularly epoxy esters dissolved in aromatic solvents, e.g., xylene, have a serious deficiency -- the inability to provide satisfactory self-recoat of coatings after overnight air-drying of the first coat. Historically, it has been necessary to allow the first coat to dry for 48 to 72 hours before attempting self-coat of such coatings. Earlier recoating has resulted in severe film lifting and film rupture or film delamination.